P5. Aggregated Load Shedding > Conclusions

Conclusions:

• Night pre-cooling may be viable long-term option for many commercial buildings to consistently reduce electric energy use and demand.

• Short-term load curtailment by shutting down chillers can provide an hour of load reduction without adverse comfort impact and without exceptional demand increases upon release from curtailment. Some commercial buildings may be able to curtail longer without comfort impacts, but there is a greater risk of increased demand upon return to normal operations.

• Aggregated load curtailment by an operator of multiple buildings on a common meter is feasible. A load shedding plan and sufficient power sub-metering and environmental monitoring capability from a single location are required prior to an event.

Commercialization potential or commercialization initiated:

Comprehensive optimal control strategies are not in common usage because controls manufacturers have yet to implement, on a widespread basis, algorithms now in the literature. Customer demand for these features is likely to increase as the installed cost of sensors and fault diagnostic systems decrease.

Utilities should be encouraged to provide monitoring tools to customers on interruptible service. This will also allow the building operator as well as the utility to confirm that actions taken resulted in verifiable load reductions.

Recommendations:

• Building automation system manufacturers should be encouraged to expand the capabilities of their products to include programmable optimization of control sequences.

• Aggregated load shedding strategies should be investigated for other building types. The strategies investigated with the simulated three-zone VAV building model may be more or less successful with other building systems.

Benefits to California:

Based on new data regarding the characteristics of California building stock and statewide energy use, the projected benefits of this project are updated as follows:

Updated Baseline:

The updated energy use data for Year 2000 is 91,771 GWh/yr and 20,741 MW for all commercial buildings. Aggregation of loads would be more likely for buildings on campuses, such as college and hospital complexes. The total load for these building types was estimated to be 13,505 GWh/yr and 3,339 MW.

Updated Outcome:

The portion of all college and hospital buildings that are on single campus-wide meters is not known. A load aggregation program applied to 50% of college and hospital load, using either thermostat set-up, night pre-cooling with ventilation, or night pre-cooling with chillers, could save 338 GWh/yr and 167 MW demand, assuming aggregate load reductions of 5% for consumption and 10% for demand.

Back to Previous Page